Angular glint calculation and analysis of radar targets via adaptive cross approximation algorithm

Angular glint is a significant electromagnetic （EM） scattering signature of extended radar targets. Based on the adaptive cross approximation （ACA） algorithm accelerated method of moments （MoM） and the plane incident wave assumption, the narrowband, wideband and newly developed high-resolution range profile （HRRP） based angular glint calculation formulations are derived and applied to arbitrarily shaped three-dimensional （3D） perfectly electrical y conducting （PEC） objects. In addition, the near-field angular glint is emphasized, which is of great importance for radarseeker applications. Furthermore, with the HRRP based angular glint, an approach to rigorously determine range resolution cel s which own relatively smal er angular glint is provided. Numerical results are presented with new findings to demonstrate the usefulness of the developed formulations.     

高密度电阻率法在红层区地下水勘查中的应用

红层区地下水资源贫乏，地表水资源分布不均及近年污染日趋严重，缺水问题十分突出，严重制约了本地区的经济发展，如何针对红层区水文地质特点，合理选择物探技术方法寻找地下水，是水文地质工作面临的十分重要的任务。本文着重介绍高密度电阻率法在红层区地下水勘查中的应用，结合各装置实例进行比较分析，结果证明了高密度电法应用在红层区地下水勘查中具有较好的实际效果和应用前景。     

基于S变换与PNN的电磁环境复杂度评估

针对复杂电磁环境定性分析和定量分级问题,提出基于广义S变换与PNN(概率神经网络)的电磁环境复杂度评估方法.应用广义S变换对电磁环境中受干扰的样本信号进行时频分析,同步提取时频域时域占用度,频域占用度和能量占用度评估参数,分析了各参数的物理意义,并给出了各评估参数的计算公式.同时增加频率重合度、调制格式相似度和背景噪声强度等评估参数,利用获取的参数训练PNN,并进行分类.仿真实验证明基于广义S变换与PNN的电磁环境复杂度评估方法在背景噪声大、训练样本数少的条件下能有效提取评估参数,并对电磁环境复杂度进行有效合理评估.     

双环静电问题的分区分离变量解研究

本文研究了在球坐标系下用带电圆环面电荷密度表象、分区分离变量法解拉普拉斯方程及推广了的电磁边值关系，一般地求解任意取向轴线相交的带电双环静电问题，并由此给出了求解非对称静电问题的典型范例．     

SYT天然电磁波法在采空区探测中的应用

阐述了采用地球物理勘测方法--SYT天然电磁渡法确定采空区位置的做法,通过3种不同的处理方式,得出相应的地质图件,并对其进行分析研究,从而在地表对采空区的位置进行了确定.     

Calculation of angular glint in near field utilizing graphical electromagnetic computing

The angular glint in the near field plays an important role on radar tracking errors. To predict it more efficiently for electrically large targets, a new method based on graphical electromagnetic computing （GRECO） is proposed. With the benefit of the graphic card, the GRECO prediction method is faster and more accurate than other methods. The proposed method at the first time considers the special case that the targets cannot be completely covered by radar beams, which makes the prediction of radar tracking errors more self-contained in practical circumstances. On the other hand, the process of the scattering center extraction is omitted, resulting in possible angular glint prediction in real time. Comparisons between the simulation results and the theoretical ones validate its correctness and value to academic research and engineering applications.     

浅析平朔安太堡矿区采空区瞬变电磁异常特征

应用瞬变电磁勘探方法对平朔煤矿采空区进行勘查,介绍了瞬变电磁法野外数据采集技术,并对采空区的瞬变电磁法视电阻率异常特征进行了分析,推断了采空区平面分布范围并经钻探验证。通过对瞬变电磁资料、地调资料、钻探资料综合解译,分析了平朔煤矿安太堡矿区不充水采空区瞬变电磁法呈现低电阻率异常特征的原因。     

基于WLAN技术的楼宇内网络建设方案及其高频电磁辐射测试分析

基于WLAN技术设计了一种楼宇内网络建设方案，给出了该方案的详细设计步骤，包括频谱环境分析、规划设计、安装施工、测试和验收共5个阶段重点论述了设计阶段，对设计阶段的关键技术进行了深入的探讨，给出了合理的解决方案．对WLAN信号的高频电磁辐射进行了专门的实验测试，并将测试结果与国家标准进行了对比，证明其对人体健康没有影响．     

Intrinsic abnormal electromagnetic medium based on polar lattice vibration

A new class of media with abnormal electromagnetic parameters has been attracting increasing attention because of its exotic properties and potential application. Currently, typical metamaterials are mainly composed of artificially designed metallic periodic structures. However, due to the limitations of available fabrication technologies, physical size and material effects, it is difficult to realize these abnormal properties by these artificial structures in the high-frequency regime. Therefore, it is important to find materials with intrinsic abnormal electromagnetic responses. In this field, a new mechanism based on the interaction between polar lattice vibrations and electromagnetic waves has been proposed. In this paper, we review progress in this field.     

电磁能量、机械能和焦耳热

电磁体系能量守恒定律中的“机械能量”应是带电体动能与焦耳热能之和。本文通过一个置于变化外磁场中带电导体圆筒的例子说明这一点,并且利用欧姆定律和电磁体系角动量守恒验证该结论的正确性。